Pin tumbler side bar cylinder lock



Nov, 25, 1969 MM. CHECK PIN TUMBLER SIDE BAR CYLINDER LOCK Filed Oct.20, 1967 3m INVENTOR. 'TfimTl-nes Q H BY CW -Ww ATTORN El United StatesPatent 3,479,849 PIN TUMBLER SIDE BAR CYLINDER LOCK Mathias M. Check, 34Bowman Drive, Greenwich, Conn. 06830 Filed Oct. 20, 1967, Ser. No.676,901 Int. Cl. Eb 27/08, /14

43.5. C]. 70-364 10 Claims ABSTRACT OF THE DISCLOSURE A new pin tumbler,side bar cylinder lock using a pivoting side bar locking device thatpivots into the groove of the change pin to affect a locking action inthe shell of the cylinder lock.

The present invention relates to a pick-resistant pin tumbler cylinderlock employing the side bar locking principle.

An object of the present invention is to provide a locking side bar ofrelatively simple construction which effectively prevents a cylinderlock from being picked by an individual applying a picking torque to thecylinder or plug.

An option of the present invention is to provide a holddown spring whichstraddles the side bars on either side of the change pin and appliespressure to the side bars to maintain the same in the proper effectivepivotal position. This hold-down spring is not absolutely necessaryexcept as one may desire further support to the side bars where 360 plugrotation and heavy duty service is anticipated.

Another object of the present invention is to provide a high securitypin tumbler lock in which some of the pins are of the conventional typewhile the remaining pins are provided with pick-resistant side barsconstructed in accordance with the teachings of the present invention.This arrangement is especially desirable when a great number of keychanges are required over the number of key changes obtained in a fullside bar locking construction and further, where key interchange isdesired to be eliminated. The term key interchange describes a conditionwhere two keys which are closely bitted to each other, might permitunintentional opening of another unmated lock. The side bar arrangementcan also be used in combination with other various types of plain orgrooved mushroom pin tumblers, disc or wafer tumblers found in otherlocks.

FIG. 1 is a partial sectional and a partial elevational view of thepick-proof cylinder lock taken along the lines 11 of FIG. 4 andemploying a side bar constructed in accordance with the teachings of myinvention, with the proper key in the keyway.

FIG. 2 is a partial sectional and a partial elevational view of thepick-resistant cylinder lock shown in FIG. 1 taken along the lines 22 ofFIG. 4 with the side bar in the locking position, which would be thecondition when no key was inserted in the keyway.

FIG. 3 is a view taken through lines 3-3 of FIG. 4 illustrating thedetails of the hold-down spring.

FIG. 4 is a perspective cut-away view of a pin tumbler cylinder lockshowing the first three pins producing a condition as illustrated inFIG. 1 and with the fourth pin shown producing the condition illustratedin FIG. 2.

FIG. 5 is a partly cross-sectional and partly elevational view of anentire pin-tumbler cylinder lock in which some of the pins are of theconventional type while other of the pins utilize side bar lockingdevices.

FIG. 6 is a partial sectional and partial elevational view of alternatemeans for pivoting the side bar locking device.

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FIG. 7 is a detail in perspective of the pivoting means illustrated onthe right hand side of FIG. 6.

Referring to the drawings, the present pin tumbler cylinder lock has anouter shell 10 and inner rotatable cylinder or plug 12. As is wellknown, the shell 10 is provided with a series of pin holes 14, eachhaving a drive pin 16 which is urged by a spring 18 toward one of thecorresponding pin holes 20 in the cylinder 12. Located in the pin hole20 are change pins 22 and 22a, the change pins 22 co-acting with theside bar are provided with angled or conical grooves 24. The partingline between the shell 10 and the cylinder 12 is identified by thereference numeral 26.

The cylinder 12 is cut-away to form a recess 28 in which is located aside bar 30 having a generally L- shaped configuration with legs 30a and30b. Also located in recess 28 is a side bar spring 32 which is housedwithin the confines of the outer shell 10 and has its end 32a in theapex of the angle formed by legs 30a and 30b of side bar 30. The sidebar spring 32 therefore ensures the proper pivoting of the side bar 30when the leg 30a of the side bar drops into tthe groove 24 of the changepin 22, all as seen in FIG. 1.

It should be noted from FIG. 1 that when the correct key K is insertedin the keyway of the cylinder 12 the change pin 22 is raised to a pointwhere the side bar 30 meshes with or enters the groove 24. When thisoccurs, the leg 30b of the side bar 30 falls within the perimeter of thekey cylinder or plug 12 permitting the cylinder to rotate freely inouter shell 10. The side bar spring 32 assists in constantly urging theside bar leg 30a into abutting engagement with the groove 24 of thechange pin when the proper key is in the keyway. However, when no keyexists in the keyway or if an improper key is inserted in the keyway,the condition as shown in FIG. 2 of the drawing occurs. When no keyexists in the keyway, the drive pin 16 and the change pin 22 are forceddownwards in the pin holes 14 and 20 respectively fully locking thecylinder 12 by the side bar locking principle. The leg 30a of the sidebar 30 abuts the straight face of the drive pin 16 and the leg 30b ofthe side bar 30 is raised to project into the locking notch 34 in theouter shell 10. In this condition, the key plug or cylinder and shellare locked together thereby preventing rotation of the key plug orcylinder 12. Applying a picking torque to the key plug will also preventfurther rotation of the plug. This is so inasmuch as the side bar 30 isdogged between the surface A of the drive pin and/or point C of thecylinder plug and shell and the surface B of the outer shell 10 as longas picking torque is maintained on the plug. This dogging preventsrotation of the key plug or cylinder 12 even if the change pins 22 areproperly positioned, thus a pick-resistant lock construction isachieved.

When the option is exercised to maintain the side bars 30 in theirproper, effective pivotal position, where heavy duty service isanticipated, a hold-down spring 36 may be inserted in the key plug orcylinder 12 as shown in FIG. 3. The spring 36 is located in grooves 31of the side bars 30 and straddles the side bars 30 thereby applyingpressure to the latter. This arrangement prevents the side bar 30 frompartially entering the locking notch 34 when the side bar is rotated inthe unlocked position. FIG. 4 shows one of the side bars 30 in thelocking position while the other side bars 30 are in the unlockedposition.

FIG. 5 illustrates the complete locking cylinder 12 together with aplurality of pin tumblers in which the first two pin tumblers are of theconventional type while the last three pin tumblers are provided with mynovel side bar locking device. This arrangement is desirable when agreater number of secure key changes are required than with a full sidebar locking construction.

It should also be noted that another option is offered in FIG. 5 for thepurpose of providing greater locking security. It should be evident thatthe length of the conventional key is designated 'by the arrow R whilethe length of the key used in the present key cylinder 12 is designatedby the arrow T. The length T is shorter than the length R. The key Kwith the length T is provided with a sharply sloping end S which engagesthe last change pin 22 so that a slight manipulation of the key, such aswithdrawing the key slightly from the keyway, will cause the last changepin 22 to drop sharply in the pin hole and thereby ensure locking of thekey plug 12 to the outer shell 10. Obviously, the construction shown inFIG. 5 will foil an attempt by a lock picker to manipulate a key whichis only slightly different from the proper key. I

In that case the lock picker attempts to align the pins properly at theparting line and thereby rotate the key plug 12 by minutely adjustingthe key in the keyway. In the present construction even a slightwithdrawal of the key in the keyway will cause the relative change pinto drop sharply in the respective pin hole thereby securely locking thekey plug and the shell together. It should also be understood that theuse of a shorter key is not mandatory to the proper working of my sidebar lock.

It should also be apparent that the specific arrangement illustrated inFIG. 5 is particularly suitable for masterkeying.

FIG. 6 shows alternate means for pivoting the side bar 30. In the righthand side of FIG. 6 a finger 38 preferably integral with key plug 12 hasan end portion 38a which projects in recess 28 of the key plug andengages at the junction of the legs 30a and 30b of the side bar 30. Theside bar therefore pivots on the end portion 38a. In the left hand sideof FIG. 6 the side bar 30 is provided with axle portions 37 which nestin complementary grooves in the key plug 12 so that the side bar 30 maypivot in a manner described hereinabove. The details of construction ofthe axle portions 37 are particularly illustrated in FIG. 7.

What I claim is:

1. A pin tumbler lock comprising an outer shell, a rotable key plug insaid outer shell, a plurality of pin holes in both said key plug andouter shell having co-acting drive pins and change pins therein, atleast one of said change pins being provided with a groove in a sidesurface thereof, a recess in said key plug extending from the pin holein which the grooved change pin is mounted, a locking notch in saidouter shell extending from said pin hole and facing said recess, apivotal side bar locking device located at least in said recess,resilient means co-acting with said side bar locking device when oneportion of said side bar locking device engages the side surface of saiddrive pin outside of said groove to apply moments of force on said sidebar locking device whereby part thereof engages positively the marginaledge of said locking notch adjacent to said drive pin to thereby pivotsaid side bar when said portion thereof enters into the groove of saidchange pin whereby the entire side 'bar is within the perimeter of saidkey plug permitting free rotation of said key plug within said outershell, and when said one portion of the side bar engages said sidesurface of said change pin said side bar pivots to cause another portionof said side bar to project into the locking notch in said outer shellthereby preventing rotational movement of said key plug in said outershell.

2. A pin tumbler cylinder lock as claimed in claim 1 whereby said sidebar locking device is of an L-shaped cross-section and said parts of theside bar are separate legs thereof.

3. A pin tumbler cylinder lock as claimed in claim 1 wherein saidresilient means is a spring having one end engaging said side bar at thejunction of said legs.

4. A pin tumbler cylinder lock as claimed in claim 1 wherein said groovein said change pin is conical-shaped.

5. A pin tumbler cylinder lock as claimed in claim 1 wherein at leastone of said change pins is provided with a smooth, uninterrupted outersurface while another of said change pins has said groove in a sidesurface thereof. said side bar being only operative with the otherchange pin having said groove.

6. A pin tumbler cylinder lock as claimed in claim 1 further comprisingspaced axle portions on said side bar and at least one complementarygroove in said key plug whereby said axle portions nest in said grooveto permit pivotal movement of said side bar.

7. A pin tumbler cylinder lock as claimed in claim 1 further comprisinga finger portion on said key plug projecting at least partially into therecess of said key plug, said side bar being seated on the end of saidfinger portion in a manner whereby said side bar is capable of pivotalmovement thereon.

8. A pin tumbler cylinder lock as claimed in claim 6 further comprisinga hold-down spring, said side bar being provided with a groove in whichpart of said holddown spring is located therein whereby said side bar isheld out of the operational area of said locking notch when said part ofthe side bar engages in the groove of said change pin.

9. A pin tumbler cylinder lock as claimed in claim 7 further comprisinga hold-down spring, said side bar being provided with a groove in whichpart of said holddown spring is located therein whereby said side bar isheld out of the operational area of said locking notch when said part ofthe side bar engages in the groove of said change pin.

10. A pin tumbler lock as claimed in claim 1 wherein said resilientmeans is a spring which exerts a compound force on said side bar lockingdevice having one vector of force in a direction transverse to thelongitudinal axis of said change pin and another vector of force at anacute angle to said first force.

References Cited UNITED STATES PATENTS 2,023,847 12/1935 Liss -3622,426,104 8/1947 Johnstone 70421 2,524,339 10/1950 Young et a1 70366MARVIN A. CHAMPION, Primary Examiner R. L. WOLFE, Assistant Examiner US.Cl. X.R. 70366. 378. 419

